Hi all! My name's Abe and i'm new here. I was hoping you could answer a few questions for me. I want to build a unit that can run games from pac-man to marvel-vs-capcom. How powerfull a system should i have(a, b, c or d)

I also was interested in *maybe* using it as a jukebox as well, but that's not really important right now. Also, i was wondering if there is any way to make the system only boot to mame?? Or do i have to load it after my OS boots? I plan on using a flavour of linux, any recomendations??